The work proposed in the present application deals with the biological effects of exposing rats simultaneously to two environmental chemicals, lead and carbon monoxide. Female rats will be exposed to lead acetate in their drinking water for 70 days prior to mating and then mated with nonexposed males. Females will also be exposed to carbon monoxide during gestation and lactation. The combined effects of these exposures will be evaluated in the offspring using behavioral neurochemical, physiological reproductive and immunological techniques. These tests will be correlated with tissue level determinations of lead.